Toán Lớp 7: Giúp em với!!!!
4^6 x 9^5 + 6^9 x 120 phần 8^4 x 3^12 -6^11
Hai phép này thui ạ!!!!!
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Toán Lớp 7: Giúp em với!!!!
4^6 x 9^5 + 6^9 x 120 phần 8^4 x 3^12 -6^11
Hai phép này thui ạ!!!!!
Comments ( 1 )
Giải đáp:
\frac{2^{30}\cdot5^{7}+2^{13}\cdot5^{27}}{2^{27}\cdot5^{7}+2^{10}\cdot5^{27}}
= [2^13 .5^7 . (2^17 + 5^20)]/[5^7 . 2^10 . (2^17 + 5^20)]
= [2^13 .5^7]/[5^7 . 2^10]
= 2^3
= 8
___________________
\frac{4^{6}\cdot9^{5}+6^{9}\cdot120}{8^{4}\cdot3^{12}-6^{11}}
= (2^12 .3^10+2^9 .3^9 .2^3. 3.5)/(2^12 .3^12−3^11 .2^11)
= (2^12 .3^10+2^12 .3^10. 5)/(2^11 .3^11 .(2.3-1))
= (2^12 .3^10 .(1+5))/(2^11 .3^11. 5)
= (2^12 .3^10 .6)/(2^11 .3^11. 5)
= [2.6]/[3.5]
= 12/15
= 4/5
$#dariana$